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From SpaceX Nuclear Experiments to Galactic Discoveries
Join host Andrew Dunkley and astronomer Fred Watson as they explore some of the most fascinating topics in space science, from innovative nuclear power tests in space to the expanding boundaries of our galaxy. Whether you're an astrophotography enthusiast or a space policy advocate, this episode delivers insights that broaden your cosmic perspective.
In this episode:
SpaceX's recent CubeSat launch featuring a tritium-based nuclear power source for space applications
The potential and safety considerations of nuclear energy in space missions
The possibility of nuclear weapons detection in space using neutron sensors and passive radiation monitoring
The intriguing hypothesis of dark matter stars and their potential signatures
The mystery surrounding Earth's dust origins—cosmic spherules and their unknown sources
New research indicating our galaxy's spiral arms are about 10% longer than previous estimates, based on light echoes from gamma ray bursts
The rise of smart telescopes and their role in making astrophotography more accessible for amateurs
Timestamps:
(00:00) Introduction and overview of today's headlines
(02:00) SpaceX's CubeSat with tritium power source—what's happening?
(04:33) Nuclear power in space: Safety and future applications
(11:03) Detecting nuclear weapons in space: Challenges and innovations
(22:45) Earth's dust origins: Micro-meteorites and cosmic spherules explained
Resources & Links:
SpaceX's CubeSat nitrogen launch story
Beta-voltaic nuclear power technology
NASA's Chandra X-ray Observatory
Universe Today article on Milky Way mapping
James Webb Space Telescope and dark matter research
Science Advances publication on Earth's micrometeorites
Connect with Fred Watson:
LinkedIn
Twitter
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Episode link: https://play.headliner.app/episode/34565447?utm_source=youtube
00:00:00 --> 00:00:01 Hi there. Thanks again for joining us.
00:00:02 --> 00:00:04 This is Space Nuts. My name is Andrew
00:00:04 --> 00:00:06 Dunley and every week we talk astronomy
00:00:06 --> 00:00:09 and space science and we answer audience
00:00:10 --> 00:00:12 questions in our alternative show which
00:00:12 --> 00:00:15 happens um well wherever you are. I mean
00:00:15 --> 00:00:17 we release it on a Monday, but that
00:00:17 --> 00:00:18 doesn't mean you listen to it on a
00:00:18 --> 00:00:22 Monday. Uh coming up today, we've got a
00:00:22 --> 00:00:26 couple of nuclear explosive stories. Uh
00:00:26 --> 00:00:29 SpaceX is involved in one of those and
00:00:29 --> 00:00:31 the other story is about uh blowing
00:00:31 --> 00:00:33 things up with atomic weapons from
00:00:33 --> 00:00:36 space. Yes, highly guaranteed, very very
00:00:36 --> 00:00:39 uh effective as well. Uh but I think
00:00:39 --> 00:00:41 there's probably a reason not to. We'll
00:00:41 --> 00:00:43 look at all of that. Uh we're also going
00:00:43 --> 00:00:46 to talk about where Earth's dust came
00:00:46 --> 00:00:47 from. Quite a bit of it, which might
00:00:48 --> 00:00:49 come as a bit of a surprise. Uh you just
00:00:49 --> 00:00:52 have to look under just about every bed
00:00:52 --> 00:00:53 and kitchen table in the world to find
00:00:53 --> 00:00:55 it. as much dust as there is in the
00:00:55 --> 00:00:58 world. But we'll see where that uh is
00:00:58 --> 00:01:01 headed. And our galaxy uh reaches out
00:01:01 --> 00:01:03 further than we thought apparently. Uh
00:01:03 --> 00:01:04 there's some interesting science behind
00:01:04 --> 00:01:07 that. We'll talk about it all on this
00:01:07 --> 00:01:09 edition of Space Nuts.
00:01:09 --> 00:01:14 >> 15 seconds. Guidance is internal. 10 9
00:01:14 --> 00:01:15 Ignition sequence start.
00:01:15 --> 00:01:16 >> Space Nuts.
00:01:16 --> 00:01:21 >> 5 4 3 2 1 2 3 4 5 4 3 2 1
00:01:21 --> 00:01:24 >> Space Nuts. Astronauts report. It feels
00:01:24 --> 00:01:25 good.
00:01:25 --> 00:01:27 >> And joining us again to talk about all
00:01:27 --> 00:01:29 of that and more is Professor Fred
00:01:29 --> 00:01:31 Watson, astronomer at large. Hello,
00:01:31 --> 00:01:32 Fred.
00:01:32 --> 00:01:34 >> Hello, Andrew. Good to see you. Good to
00:01:34 --> 00:01:37 see you today. Yes. We sort of missed a
00:01:37 --> 00:01:38 few days, haven't we?
00:01:38 --> 00:01:40 >> Yes. You've been you've been off uh
00:01:40 --> 00:01:42 you've been off conferencing.
00:01:42 --> 00:01:45 >> Yes. So, the annual science meeting as
00:01:45 --> 00:01:47 it's called of the National Astronomy
00:01:47 --> 00:01:48 Society, the Astronomical Society of
00:01:48 --> 00:01:50 Australia. It's where all the
00:01:50 --> 00:01:52 professional astronomers get together
00:01:52 --> 00:01:53 and uh talk about what they've been
00:01:53 --> 00:01:56 doing, their research. Uh it was a big
00:01:56 --> 00:01:59 meeting. There were I would have guessed
00:02:00 --> 00:02:01 maybe a couple of hundred people there
00:02:01 --> 00:02:03 altogether. Uh that's quite big for
00:02:03 --> 00:02:05 astronomers and in a country that's only
00:02:05 --> 00:02:07 got 700 astronomers in it.
00:02:07 --> 00:02:08 >> Yeah.
00:02:08 --> 00:02:11 >> Uh but um what was interesting and what
00:02:11 --> 00:02:14 was very I think heartening for me was
00:02:14 --> 00:02:17 the number of youngsters that were
00:02:17 --> 00:02:18 there. I call them you because you know
00:02:18 --> 00:02:21 people under 50
00:02:21 --> 00:02:23 people um the the new generation of
00:02:23 --> 00:02:25 astronomers uh most of them whom I
00:02:25 --> 00:02:27 didn't know and they have no idea who I
00:02:27 --> 00:02:30 am and that's fine uh that all was okay.
00:02:30 --> 00:02:33 It just contrasts with a few years ago.
00:02:33 --> 00:02:34 So when I was the astronomer in charge
00:02:34 --> 00:02:37 of the of the observatory at Kuna
00:02:37 --> 00:02:39 Barabbran uh we were kind of the
00:02:39 --> 00:02:41 shopkeepers. So all these astronomers
00:02:41 --> 00:02:43 used to come through stay in the lodge
00:02:43 --> 00:02:45 and do their research using the
00:02:45 --> 00:02:47 telescope. So I knew a a large fraction
00:02:48 --> 00:02:50 of the astronomical population of
00:02:50 --> 00:02:52 Australia, but that's changed uh because
00:02:52 --> 00:02:56 my job that job is no longer mine. Uh
00:02:56 --> 00:02:58 and so I don't see people the same way.
00:02:58 --> 00:03:00 But uh it was so it was very nice to
00:03:00 --> 00:03:02 meet a lot of new faces and catch up
00:03:02 --> 00:03:04 with some very old faces as well, some
00:03:04 --> 00:03:07 even older than mine. Um and we also
00:03:07 --> 00:03:10 discussed matters such as the future of
00:03:10 --> 00:03:13 Australian astronomy because that's uh
00:03:13 --> 00:03:16 in a interesting state at the moment
00:03:16 --> 00:03:19 with the government having declined uh
00:03:19 --> 00:03:22 to uh engage in membership with the
00:03:22 --> 00:03:24 European Southern Observatory. We are
00:03:24 --> 00:03:27 now working on plan B uh and uh well it
00:03:27 --> 00:03:28 looks promising.
00:03:28 --> 00:03:30 >> Yes, fingers crossed. Uh there's a lot
00:03:30 --> 00:03:34 going on. Okay. Um, we should probably
00:03:34 --> 00:03:36 get stuck into these stories cuz there's
00:03:36 --> 00:03:38 a lot to discuss. The first story is a
00:03:38 --> 00:03:41 double banger about um nuclear energy
00:03:41 --> 00:03:44 and atomic weapons. Uh, we'll start off
00:03:44 --> 00:03:48 with the story about Space X and they're
00:03:48 --> 00:03:51 um they're looking at nuclear power in
00:03:51 --> 00:03:53 space, nuclearpowered satellites. What's
00:03:53 --> 00:03:56 the story here? It's a test launch
00:03:56 --> 00:04:00 really a launch of a a a cubat basically
00:04:00 --> 00:04:03 that um has not a nuclear reactor inside
00:04:03 --> 00:04:07 but a um basically a capsule of
00:04:07 --> 00:04:08 something called tritium which is
00:04:08 --> 00:04:10 sometimes called heavy hydrogen. It's
00:04:10 --> 00:04:13 hydrogen with two neutrons in it as well
00:04:13 --> 00:04:16 as the proton at its center and it's
00:04:16 --> 00:04:19 radioactive. Uh tritium is um I I
00:04:19 --> 00:04:20 suppose you'd call it mildly
00:04:20 --> 00:04:24 radioactive. Um, we used to use tritium
00:04:24 --> 00:04:26 standard lamps uh at the observatory
00:04:26 --> 00:04:28 when I was working there, which was a
00:04:28 --> 00:04:30 little capsule of tritium with some
00:04:30 --> 00:04:34 phosphor on it. Um, and the the um
00:04:34 --> 00:04:36 basically the electrons released by the
00:04:36 --> 00:04:39 tritium lit up the phosphor and and gave
00:04:39 --> 00:04:41 a very constant glow so we could use it
00:04:41 --> 00:04:44 to calibrate other other instruments.
00:04:44 --> 00:04:47 So, I've been close up and personal with
00:04:47 --> 00:04:49 um a little nuclear power source a bit
00:04:49 --> 00:04:51 like that, but it was just making faint
00:04:51 --> 00:04:54 light. This one is one that's been uh
00:04:54 --> 00:04:58 developed by a private company um and
00:04:58 --> 00:05:01 it's uh basically a company called City
00:05:01 --> 00:05:04 Labs uh in the United States. uh they've
00:05:04 --> 00:05:08 built um a little as I said it's
00:05:08 --> 00:05:11 effectively a cubat which has this um
00:05:11 --> 00:05:13 little nuclear
00:05:13 --> 00:05:15 not nuclear reactor but nuclear power
00:05:15 --> 00:05:18 source inside a tritium uh source that
00:05:18 --> 00:05:20 I've just been talking about which
00:05:20 --> 00:05:22 doesn't actually convert the electrons
00:05:22 --> 00:05:26 into light it converts them directly
00:05:26 --> 00:05:29 into electricity so they've got these
00:05:29 --> 00:05:31 panels on the side of it that take the
00:05:31 --> 00:05:33 electrons that come from the tritium and
00:05:33 --> 00:05:34 turn
00:05:34 --> 00:05:38 straight into um into electricity. It's
00:05:38 --> 00:05:41 called bore bhr. Uh which is a bit of a
00:05:41 --> 00:05:43 play on words because Neils Boore was
00:05:43 --> 00:05:45 one of the great founders of quantum
00:05:45 --> 00:05:49 theory. Uh same spelling um Danish one
00:05:49 --> 00:05:52 uh a Danish uh scientist uh and it
00:05:52 --> 00:05:56 stands for beta voltaic and a beta
00:05:56 --> 00:05:58 voltaque is taking the beta particles
00:05:58 --> 00:06:01 which are otherwise known as electrons
00:06:01 --> 00:06:03 uh turning them into electricity. So
00:06:03 --> 00:06:05 it's beta voltake orbital high
00:06:05 --> 00:06:07 reliability spacecraft. That's where you
00:06:07 --> 00:06:09 get the BR from.
00:06:09 --> 00:06:12 >> Uh and it's been it's been launched. So
00:06:12 --> 00:06:14 SpaceX's part in this story is just to
00:06:14 --> 00:06:17 provide the taxi uh up into um up into
00:06:17 --> 00:06:20 orbit. It's a trans transporter mission.
00:06:20 --> 00:06:23 One of um one of basically one of
00:06:23 --> 00:06:25 SpaceX's taxi rides to get stuff up and
00:06:25 --> 00:06:29 down from up to orbit. Coming down is a
00:06:29 --> 00:06:31 different story. Most of them just burn
00:06:31 --> 00:06:35 up. Uh yes, but it is uh probably the
00:06:35 --> 00:06:38 first cubat to include a nuclear power
00:06:38 --> 00:06:42 system. Uh and maybe just maybe will
00:06:42 --> 00:06:44 sort of illuminate the way for a new
00:06:44 --> 00:06:47 generation of uh of spacecraft which are
00:06:47 --> 00:06:49 equipped with uh with these nuclear
00:06:49 --> 00:06:51 power sources. I suppose they have to
00:06:51 --> 00:06:54 look at alternatives because we we've
00:06:54 --> 00:06:57 been reliant fairly reliant anyway on
00:06:57 --> 00:07:00 solar energy in space um particularly
00:07:00 --> 00:07:02 with our orbiting satellites but also
00:07:02 --> 00:07:05 with um the international space station
00:07:06 --> 00:07:09 and others u but the the time will come
00:07:09 --> 00:07:12 where we are in places where there won't
00:07:12 --> 00:07:14 be that much
00:07:14 --> 00:07:17 >> sunlight and in some places there won't
00:07:17 --> 00:07:19 be any at all and you know solar panels
00:07:19 --> 00:07:21 are going to be useless. Uh that's
00:07:21 --> 00:07:23 correct. And and we've seen already the
00:07:24 --> 00:07:27 um the use of these uh RTGs, radio
00:07:27 --> 00:07:30 isotope thermmoelectric generators,
00:07:30 --> 00:07:32 >> uh which are carried by both the
00:07:32 --> 00:07:36 Curiosity and the uh Perseverance rovers
00:07:36 --> 00:07:39 uh as well as spacecraft in deep space
00:07:39 --> 00:07:42 like uh Voyager One, Voyager 2,
00:07:42 --> 00:07:44 Pioneers, I think they've got them as
00:07:44 --> 00:07:46 well. And these are spacecraft that are
00:07:46 --> 00:07:48 so far from the sun that you get very
00:07:48 --> 00:07:51 little light from the sun uh in terms of
00:07:51 --> 00:07:52 um you know using it to generate
00:07:52 --> 00:07:54 electricity. So they've they've had
00:07:54 --> 00:07:56 their nuclear power sources for a long
00:07:56 --> 00:07:58 time. They are quite different though
00:07:58 --> 00:07:59 from what we're talking about here.
00:07:59 --> 00:08:02 There are I think it's 13 kg if I
00:08:02 --> 00:08:03 remember rightly is the amount in a
00:08:03 --> 00:08:07 canister of plutonium dioxide
00:08:07 --> 00:08:09 >> which is decaying all the time and
00:08:09 --> 00:08:11 getting very hot as it does that. And
00:08:11 --> 00:08:14 that heat is then used to generate
00:08:14 --> 00:08:18 electricity. Uh and it actually dies
00:08:18 --> 00:08:21 away as time goes on. So these uh
00:08:21 --> 00:08:23 nuclear RTGs, the radioisotope
00:08:23 --> 00:08:25 thermmoelectric generators gradually
00:08:25 --> 00:08:29 lose their power. Um and that's why we
00:08:29 --> 00:08:31 hear from time to time, and we usually
00:08:31 --> 00:08:34 report this on on Space Nuts, we hear of
00:08:34 --> 00:08:36 uh uh instruments on board Voyager One
00:08:36 --> 00:08:39 being turned off to save to save the
00:08:39 --> 00:08:39 power.
00:08:39 --> 00:08:41 >> Yeah. And that that didn't that happened
00:08:41 --> 00:08:43 again not so long ago, I think. But um
00:08:44 --> 00:08:45 >> that that's correct. Yes, it did. There
00:08:45 --> 00:08:48 was one turned off quite recently. But
00:08:48 --> 00:08:50 but perhaps more to the point and your
00:08:50 --> 00:08:52 uh what you've just said about there
00:08:52 --> 00:08:53 being some places that have no sunlight
00:08:53 --> 00:08:57 whatsoever. Uh that applies to the uh
00:08:57 --> 00:09:00 those deep craters near the moon's south
00:09:00 --> 00:09:02 pole. And that's where we're thinking of
00:09:02 --> 00:09:06 exploring. So it may be that um these
00:09:06 --> 00:09:11 beta voltaic arrays uh uh or devices
00:09:11 --> 00:09:14 might well be the future of power
00:09:14 --> 00:09:16 generation on the near the moon south
00:09:16 --> 00:09:18 pole because you're in places where
00:09:18 --> 00:09:20 there's no light whatsoever from the
00:09:20 --> 00:09:21 sun.
00:09:21 --> 00:09:23 >> Absolutely true. Darn cold too. It is.
00:09:23 --> 00:09:26 >> It is. It's always cold there. Yes. Yes.
00:09:26 --> 00:09:28 >> Indeed. Uh that's uh it's a really
00:09:28 --> 00:09:31 interesting story and uh we're obviously
00:09:31 --> 00:09:33 in the early phases of finding these
00:09:33 --> 00:09:36 alternatives. Is um is treatium safe?
00:09:36 --> 00:09:40 >> Uh it's probably something regarded uh
00:09:40 --> 00:09:44 treated carefully. Uh it it is it is
00:09:44 --> 00:09:46 generally safe. I mean we never took any
00:09:46 --> 00:09:48 real precautions with the device that we
00:09:48 --> 00:09:51 had on the telescope and maybe we should
00:09:51 --> 00:09:54 have done although uh most of us are
00:09:54 --> 00:09:57 still around and in fairly good health
00:09:57 --> 00:10:01 but um yes they are releasing electrons
00:10:01 --> 00:10:05 uh beta radiation. It's um uh if you if
00:10:05 --> 00:10:07 you had a high level though of tritium,
00:10:07 --> 00:10:09 if you had a you know significant amount
00:10:09 --> 00:10:10 of it, then you would have to be careful
00:10:10 --> 00:10:12 about how you handled it and where it
00:10:12 --> 00:10:14 was put and if it needed shielding and
00:10:14 --> 00:10:15 things of that sort.
00:10:15 --> 00:10:17 >> Yeah. So don't sprinkle it on your corn
00:10:17 --> 00:10:19 flakes or anything like that.
00:10:19 --> 00:10:20 >> Yes, that's right. It's best to avoid it
00:10:20 --> 00:10:21 if you can.
00:10:21 --> 00:10:22 >> Yeah.
00:10:22 --> 00:10:25 >> Sugar's damaging enough already. Um
00:10:25 --> 00:10:27 >> it is
00:10:27 --> 00:10:29 about it. If you'd like to um read up on
00:10:29 --> 00:10:31 that story about the uh the launch of
00:10:31 --> 00:10:34 the Cubat with the Tritium uh nuclear
00:10:34 --> 00:10:36 power device that they're testing, uh
00:10:36 --> 00:10:38 you can read about it at daily
00:10:38 --> 00:10:41 galaxy.com.
00:10:41 --> 00:10:44 Um let's keep on this theme, Fred,
00:10:44 --> 00:10:47 because that's the good news. Uh the bad
00:10:47 --> 00:10:51 news is um the the problem of exploding
00:10:51 --> 00:10:54 nuclear devices in space or firing
00:10:54 --> 00:10:56 nuclear devices from space to targets on
00:10:56 --> 00:10:59 Earth. That's that's a real issue. I
00:10:59 --> 00:11:02 know um was it back in the8s the Star
00:11:02 --> 00:11:04 Wars
00:11:04 --> 00:11:08 um um push was uh all the rage in the
00:11:08 --> 00:11:10 news at the time that got shut down
00:11:10 --> 00:11:12 pretty quickly.
00:11:12 --> 00:11:15 >> Star Wars was um a Reagan era
00:11:15 --> 00:11:17 initiative. Uh yes, I think it was I
00:11:17 --> 00:11:19 think it was um
00:11:19 --> 00:11:21 >> uh basically electromagnetic radiation
00:11:21 --> 00:11:23 to to zap your satellites. It wasn't
00:11:23 --> 00:11:25 nuclear though. Uh because nuclear
00:11:25 --> 00:11:28 weapons are in space are prohibited by
00:11:28 --> 00:11:31 the outer space treaty 1967.
00:11:31 --> 00:11:32 >> So what's happening?
00:11:32 --> 00:11:36 >> They're not allowed but
00:11:36 --> 00:11:39 um there may be some there uh launched
00:11:39 --> 00:11:40 by
00:11:40 --> 00:11:43 >> powers that um stretch the envelope if I
00:11:44 --> 00:11:46 can put it that way. Governments that
00:11:46 --> 00:11:48 stretch the envelope. Uh and we don't
00:11:48 --> 00:11:50 know uh we don't know if there are any.
00:11:50 --> 00:11:53 we, you know, they're banned by the uh
00:11:53 --> 00:11:54 outer space treaty, so there shouldn't
00:11:54 --> 00:11:58 be any nuclear weapons in space, but
00:11:58 --> 00:12:01 that's all very well. Um there's a lot
00:12:01 --> 00:12:03 of things that shouldn't happen that do
00:12:03 --> 00:12:06 happen. And um so it may be that perhaps
00:12:06 --> 00:12:09 there are nuclear weapons in space. So
00:12:09 --> 00:12:11 the the question is
00:12:11 --> 00:12:13 um how how do you detect them if there
00:12:13 --> 00:12:16 are these weapons? M
00:12:16 --> 00:12:21 >> um and um that's where this piece of
00:12:21 --> 00:12:24 research uh from the Massachusetts
00:12:24 --> 00:12:27 Institute of Technology has come from.
00:12:27 --> 00:12:31 It's um a a person whose name is Aric
00:12:31 --> 00:12:34 Danagulian. Uh sounds like an Armenian
00:12:34 --> 00:12:36 name, does it? Usually I on the end
00:12:36 --> 00:12:38 Armenian and associate professor of
00:12:38 --> 00:12:41 nuclear science and engineering at the
00:12:41 --> 00:12:43 Massachusetts Institute of Technology.
00:12:43 --> 00:12:48 and he has um essentially uh thought of
00:12:48 --> 00:12:52 a neat way of
00:12:52 --> 00:12:57 of building a device that you could fly
00:12:57 --> 00:13:01 in the vicinity of a satellite to detect
00:13:01 --> 00:13:04 whether it is carrying nuclear weapons.
00:13:04 --> 00:13:07 Um and it's all about the subatomic
00:13:07 --> 00:13:11 particles uh that um you know that that
00:13:11 --> 00:13:14 uh nuclear weapons are all about. It's
00:13:14 --> 00:13:16 all about
00:13:16 --> 00:13:18 >> neutrons and uh you know the nuclear
00:13:18 --> 00:13:20 nuclei of atoms that's where it all
00:13:20 --> 00:13:21 comes from.
00:13:21 --> 00:13:25 >> Um so what he's
00:13:25 --> 00:13:29 what he has suggested that I might quote
00:13:29 --> 00:13:33 um I might quote from uh from Dr. to
00:13:33 --> 00:13:38 Danagolian's work. Uh the
00:13:38 --> 00:13:41 risk is that if if you did explode a
00:13:41 --> 00:13:43 nuclear weapon in low Earth orbit, then
00:13:43 --> 00:13:46 you basically wreck low Earth orbit for
00:13:46 --> 00:13:48 everybody. It's not the blast. It's just
00:13:48 --> 00:13:51 the the subatomic particles that do it.
00:13:51 --> 00:13:53 >> Uh and so what he goes on to say is this
00:13:54 --> 00:13:56 danger is compounded by the lack of a
00:13:56 --> 00:13:58 verification mechanism for the outer
00:13:58 --> 00:14:03 space treaty. um there's no detection
00:14:03 --> 00:14:05 methodologies that have been proposed in
00:14:05 --> 00:14:07 the scientific literature. So what he's
00:14:07 --> 00:14:09 saying is here's a concept and
00:14:09 --> 00:14:12 feasibility study uh for verifying a
00:14:12 --> 00:14:15 satellite's compliance to the outer
00:14:15 --> 00:14:18 space treaty by observing the neutrons
00:14:18 --> 00:14:20 induced by spolation from the
00:14:20 --> 00:14:24 approximately giga electric vol giga
00:14:24 --> 00:14:27 electron volt protons in the inner allen
00:14:27 --> 00:14:29 radiation belt which is a slightly
00:14:29 --> 00:14:32 complicated and technical way of saying
00:14:32 --> 00:14:34 uh you've already got subatomic
00:14:34 --> 00:14:37 particles in the radiation belt around
00:14:37 --> 00:14:41 around our planet. Um if you can um
00:14:41 --> 00:14:47 basically watch the way uh a satellite
00:14:47 --> 00:14:49 responds to those protons that are in
00:14:49 --> 00:14:53 the radiation belts. Um if for example
00:14:53 --> 00:14:54 that bombardment of protons from the
00:14:54 --> 00:14:58 radiation belts causes neutrons to be uh
00:14:58 --> 00:15:02 emitted then you can uh have a fair
00:15:02 --> 00:15:05 degree of um confidence that there might
00:15:05 --> 00:15:07 be a nuclear weapon on board or a lot of
00:15:07 --> 00:15:10 nuclear file material heavy elements
00:15:10 --> 00:15:13 like uranium. That's the kind of thing
00:15:13 --> 00:15:17 that this is all about. Um and so um
00:15:17 --> 00:15:21 what uh you know what what this is all
00:15:21 --> 00:15:25 about is uh building a satellite that
00:15:25 --> 00:15:27 can detect
00:15:27 --> 00:15:29 uh neutrons
00:15:29 --> 00:15:33 uh coming from radioactive material. and
00:15:33 --> 00:15:37 he's basically suggesting a a detector
00:15:37 --> 00:15:40 uh a what he calls an inspector
00:15:40 --> 00:15:43 satellite that flies by uh the the
00:15:43 --> 00:15:45 satellite that you're interested in
00:15:45 --> 00:15:46 finding out whether it's got nuclear
00:15:46 --> 00:15:47 weapons.
00:15:47 --> 00:15:49 >> And it's got these detectors uh which
00:15:49 --> 00:15:51 are almost like X-ray detectors, the
00:15:51 --> 00:15:54 kind of things that you see now in in
00:15:54 --> 00:15:55 when you go for an X-ray, a chest X-ray.
00:15:55 --> 00:15:57 They're electronic. They're not
00:15:57 --> 00:15:58 photographic like they used to be back
00:15:58 --> 00:15:59 in the day.
00:15:59 --> 00:16:01 >> Yeah. Um, and they've got what are
00:16:01 --> 00:16:03 called neutron sensors. Uh, they're
00:16:03 --> 00:16:06 called scintillators. And you put uh you
00:16:06 --> 00:16:09 put those in a special arrangement with
00:16:09 --> 00:16:13 other basically other detectors. Uh, and
00:16:13 --> 00:16:16 um if you do that then you can you can
00:16:16 --> 00:16:19 apparently sort out the neutrons from
00:16:19 --> 00:16:22 the other natural subatomic particles
00:16:22 --> 00:16:24 that are floating around near the
00:16:24 --> 00:16:26 radiation belts. And the neutrons come
00:16:26 --> 00:16:28 from radioactive material. And you can
00:16:28 --> 00:16:30 also see the direction that they're
00:16:30 --> 00:16:32 coming from. So you can sort of point
00:16:32 --> 00:16:35 this thing towards your target satellite
00:16:35 --> 00:16:37 uh the one that you suspect might have
00:16:37 --> 00:16:39 nuclear weapons and and it will give you
00:16:39 --> 00:16:41 the direction of where it's coming from.
00:16:41 --> 00:16:47 >> Um and so uh just a quote um from again
00:16:47 --> 00:16:50 from Dr. Danagulian. Um the calculations
00:16:50 --> 00:16:54 show that a 9 unitit cubat size
00:16:54 --> 00:16:56 detection platform that's something the
00:16:56 --> 00:16:58 size of what's that about three loaves
00:16:58 --> 00:16:59 of bread something of that sort size
00:17:00 --> 00:17:03 it's quite small um it can identify a
00:17:03 --> 00:17:06 thermonuclear weapon from a distance of
00:17:06 --> 00:17:09 4 kilometers in approximately one week
00:17:09 --> 00:17:12 of observation. Now, that's quite a long
00:17:12 --> 00:17:13 time,
00:17:13 --> 00:17:16 >> but uh apparently if you could get it to
00:17:16 --> 00:17:18 within 1 kilometer, it would take you
00:17:18 --> 00:17:21 about an hour to detect a weapon.
00:17:21 --> 00:17:25 >> And that's promising. That's one flyby.
00:17:25 --> 00:17:28 That's, you know, an hour of proximity.
00:17:28 --> 00:17:31 Uh you could do that as you go past the
00:17:31 --> 00:17:33 the suspect the suspect satellite if you
00:17:33 --> 00:17:36 got an hour in in uh close contact with
00:17:36 --> 00:17:39 it or close uh proximity to it within a
00:17:39 --> 00:17:42 within a kilometer uh then you might
00:17:42 --> 00:17:45 well detect a nuclear weapon on board.
00:17:45 --> 00:17:46 And of course you could improve that if
00:17:46 --> 00:17:49 you had more than one of these inspector
00:17:49 --> 00:17:51 satellites. If you multiplied them up
00:17:51 --> 00:17:53 then you could get quite significant
00:17:53 --> 00:17:55 improvements in that performance. So
00:17:55 --> 00:17:57 it's really quite interesting. Yeah.
00:17:57 --> 00:18:01 >> Um, uh, one quote that I really liked,
00:18:01 --> 00:18:04 um, and and it's I'm going to read, uh,
00:18:04 --> 00:18:07 from Universe Today has a very nice
00:18:07 --> 00:18:09 article on this. The last sentence is,
00:18:09 --> 00:18:10 right now, nations like the USA and
00:18:10 --> 00:18:13 Russia rely on intelligence to know what
00:18:13 --> 00:18:15 the other is doing. And as we know from
00:18:15 --> 00:18:17 history, intelligence can get things
00:18:17 --> 00:18:20 wrong. You can fake intelligence, said
00:18:20 --> 00:18:23 Dr. Danagulian, but you can't fake
00:18:23 --> 00:18:26 physics. I like that. It's true. So you
00:18:26 --> 00:18:28 could do it by physics. Yeah,
00:18:28 --> 00:18:31 >> they do mention in this particular
00:18:31 --> 00:18:33 article that there's one suspect
00:18:33 --> 00:18:34 satellite that seems to have been
00:18:34 --> 00:18:37 launched by Russia. And the bottom line
00:18:37 --> 00:18:40 is that it's it's been put in an orbit
00:18:40 --> 00:18:42 that is very strange
00:18:42 --> 00:18:46 >> and very hostile in terms of its
00:18:46 --> 00:18:48 radiation uh in that area. And the
00:18:48 --> 00:18:51 question is asked, well, it says no one
00:18:51 --> 00:18:52 puts satellites there because it's
00:18:52 --> 00:18:54 highly radioactive. Why would you put a
00:18:54 --> 00:18:56 satellite in that orbit?
00:18:56 --> 00:18:58 >> So that's one. They've already they
00:18:58 --> 00:19:01 haven't identified as maybe carrying a
00:19:01 --> 00:19:03 nuclear weapon, but they've certainly
00:19:03 --> 00:19:05 identified it as suspicious.
00:19:05 --> 00:19:08 >> Yes, that's correct. And so um yes,
00:19:08 --> 00:19:10 highlighting that I think you know puts
00:19:10 --> 00:19:13 this article in context. It um it tells
00:19:13 --> 00:19:15 you that this is a real issue and um we
00:19:15 --> 00:19:17 kind of need to work on how you might
00:19:17 --> 00:19:20 detect nuclear weapons in space. it. Of
00:19:20 --> 00:19:21 course, the other side of it is if you
00:19:22 --> 00:19:23 do identify a satellite that's carrying
00:19:24 --> 00:19:25 a nuclear weapon,
00:19:25 --> 00:19:27 >> what do you do next? It's like it's like
00:19:27 --> 00:19:29 trying to teach people not to overtake
00:19:29 --> 00:19:31 in merging lanes, isn't it?
00:19:31 --> 00:19:35 >> Uh yes. Uh but um it's worse than that
00:19:36 --> 00:19:38 really because a little bit. Yeah. You
00:19:38 --> 00:19:41 know, we have nations that completely
00:19:41 --> 00:19:44 disregard international law. They invade
00:19:44 --> 00:19:48 other countries without um so much as a
00:19:48 --> 00:19:53 you know a sniff of the um um of the um
00:19:53 --> 00:19:55 all the international treaties. They
00:19:55 --> 00:19:57 just run a muck among them and away they
00:19:57 --> 00:19:58 go.
00:19:58 --> 00:20:00 >> Uh and yes so that's the possibility
00:20:00 --> 00:20:02 that we might already have them. There
00:20:02 --> 00:20:06 there is a kind of corollary corollery
00:20:06 --> 00:20:08 of this which I was thinking of when
00:20:08 --> 00:20:11 when I read this story. Um and that is
00:20:11 --> 00:20:16 that back in the 70s uh gammaray
00:20:16 --> 00:20:19 satellites were launched satellites that
00:20:19 --> 00:20:21 detect gamma radiation and that was to
00:20:21 --> 00:20:26 detect any inmosphere nuclear tests uh
00:20:26 --> 00:20:28 conducted on earth. uh because there was
00:20:28 --> 00:20:30 a test ban treaty that was signed uh
00:20:30 --> 00:20:33 that all the signatories said no we
00:20:33 --> 00:20:35 won't test uh nuclear weapons in the
00:20:35 --> 00:20:38 atmosphere. Uh but they had to verify it
00:20:38 --> 00:20:41 and so the verification process involved
00:20:41 --> 00:20:42 uh a number of satellites being launched
00:20:42 --> 00:20:44 that could detect gamma rays which would
00:20:44 --> 00:20:46 be emitted by a nuclear bomb being
00:20:46 --> 00:20:49 detonated in in the atmosphere. Uh now
00:20:50 --> 00:20:52 none were none were but those satellites
00:20:52 --> 00:20:55 are what detected gammaray bursts these
00:20:55 --> 00:20:57 um you know fascinating pulses of
00:20:57 --> 00:21:00 radiation that come from uh from
00:21:00 --> 00:21:02 explosions deep in space.
00:21:02 --> 00:21:04 >> Yeah. Of course not man-made explosions
00:21:04 --> 00:21:06 but natural ones. Yes.
00:21:06 --> 00:21:09 >> Cuz if they do start detecting nuclear
00:21:09 --> 00:21:12 weapons in space then the parties
00:21:12 --> 00:21:14 involved uh they won't say oh sorry
00:21:14 --> 00:21:15 we'll take them all down. They'll
00:21:16 --> 00:21:18 they'll find ways of hiding them.
00:21:18 --> 00:21:21 >> Probably. Yes, that's probably right.
00:21:21 --> 00:21:23 >> Gosh, it's tough, isn't it?
00:21:23 --> 00:21:25 >> Uh tough world we live in
00:21:25 --> 00:21:27 >> indeed. Uh and beyond it in some
00:21:27 --> 00:21:28 respects.
00:21:28 --> 00:21:30 >> Uh you can read that story at
00:21:30 --> 00:21:32 universetoday.com.
00:21:32 --> 00:21:34 This is Space Nuts with Andrew Dunley
00:21:34 --> 00:21:37 and Professor Fred Watson.
00:21:37 --> 00:21:39 >> Let's take a short break from the show
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00:23:26 --> 00:23:28 Roger. Your last here also
00:23:28 --> 00:23:30 >> space nuts.
00:23:30 --> 00:23:34 >> Our next story, Fred, uh is looking at
00:23:34 --> 00:23:36 uh all the dust on Earth and where it
00:23:36 --> 00:23:38 might have come from. Now, I was
00:23:38 --> 00:23:41 thinking cats because, you know, they do
00:23:41 --> 00:23:44 shed. Uh but it's uh it's a bit more
00:23:44 --> 00:23:47 involved than that. And and what is
00:23:47 --> 00:23:49 really interesting about this story is
00:23:49 --> 00:23:51 they they think a heck of a lot of it
00:23:51 --> 00:23:54 came from one source.
00:23:54 --> 00:23:56 That's right. and it's a mysterious one
00:23:56 --> 00:24:00 as well. Um so this is quite a nice
00:24:00 --> 00:24:03 story uh from uh published in Science
00:24:03 --> 00:24:08 Advances. Um it's about uh the
00:24:08 --> 00:24:11 micrometeorites that bombard the earth
00:24:12 --> 00:24:15 and it's a bit surprising this stuff. Uh
00:24:16 --> 00:24:18 you know we think of meteorites as big
00:24:18 --> 00:24:19 chunks of rock that come through the
00:24:19 --> 00:24:22 atmosphere. they have a blaze of glory
00:24:22 --> 00:24:24 and then land on the earth somewhere.
00:24:24 --> 00:24:25 And
00:24:25 --> 00:24:29 what we've got there is a is um a free
00:24:29 --> 00:24:32 sample of of extraterrestrial material.
00:24:32 --> 00:24:33 Uh but there are also these
00:24:34 --> 00:24:36 micrometeorites which rain on the
00:24:36 --> 00:24:37 earth's atmosphere and they're dust
00:24:37 --> 00:24:39 particles as you've kind of hinted.
00:24:39 --> 00:24:40 >> Yeah.
00:24:40 --> 00:24:44 >> Uh they um and they're sort of always
00:24:44 --> 00:24:48 falling on Earth. Uh and that uh is
00:24:48 --> 00:24:51 again it's a free gift from space. Um I
00:24:51 --> 00:24:54 think so I was sort of vaguely involved
00:24:54 --> 00:24:57 with this stuff probably 50 years ago
00:24:57 --> 00:25:00 back in the 70s. I think they were then
00:25:00 --> 00:25:02 called Brownly particles. Um so I think
00:25:02 --> 00:25:05 that's what we're talking about. Yeah.
00:25:05 --> 00:25:08 Uh but they're now I think called cosmic
00:25:08 --> 00:25:10 ferals. I should check whether Brownley
00:25:10 --> 00:25:13 particles and cos cosmic ferals are the
00:25:13 --> 00:25:17 same thing. But basically what they what
00:25:17 --> 00:25:20 they are is bits of meteor meteor that
00:25:20 --> 00:25:23 have melted as they come down through
00:25:23 --> 00:25:26 the earth's atmosphere. But they
00:25:26 --> 00:25:27 they they actually survive into the
00:25:28 --> 00:25:30 inner atmosphere and they cool down and
00:25:30 --> 00:25:32 they form a little sphere because the um
00:25:32 --> 00:25:35 basically the surface tension of molten
00:25:35 --> 00:25:37 material brings them into a sphere. Uh
00:25:37 --> 00:25:43 and that uh is the story so far because
00:25:43 --> 00:25:46 that um heating that you that they
00:25:46 --> 00:25:48 experience as the as the sort of parent
00:25:48 --> 00:25:51 body, the meteor meteor or meteorite as
00:25:51 --> 00:25:55 it comes through the atmosphere, it uh
00:25:55 --> 00:25:57 kind of destroys their chemical
00:25:57 --> 00:25:59 structure. You know that the minerals in
00:25:59 --> 00:26:02 it get get metamorphosed. They get
00:26:02 --> 00:26:03 changed because they've been subject to
00:26:03 --> 00:26:05 very high temperatures.
00:26:05 --> 00:26:08 >> Yeah. Um but there is a technique uh
00:26:08 --> 00:26:13 that allows you to look at uh some of
00:26:13 --> 00:26:16 the characteristics of these objects
00:26:16 --> 00:26:19 that is not destroyed by heat and it's
00:26:19 --> 00:26:24 the oxygen isotope signature uh which
00:26:24 --> 00:26:25 we've talked about before. We've talked
00:26:25 --> 00:26:27 about isotopes and how they uh you know
00:26:28 --> 00:26:29 how we distinguish between heavy water
00:26:29 --> 00:26:31 and normal water and all of that sort of
00:26:31 --> 00:26:32 thing. M
00:26:32 --> 00:26:35 >> uh that's so it's basically the the
00:26:35 --> 00:26:38 number of neutrons in a in an atom. Um
00:26:38 --> 00:26:42 so you've got these oxygen signatures
00:26:42 --> 00:26:47 uh that um essentially uh let you uh
00:26:47 --> 00:26:51 group these cosmic sphererals, the
00:26:51 --> 00:26:53 Brownly particles if that's what they
00:26:53 --> 00:26:56 are. Um and it turns out that so so
00:26:56 --> 00:26:59 people do you know they do population
00:26:59 --> 00:27:01 census statistics on these objects to
00:27:01 --> 00:27:05 find out what uh what relationships they
00:27:05 --> 00:27:07 bear with one another.
00:27:07 --> 00:27:10 About 10% of them uh of these fererals
00:27:10 --> 00:27:12 that have been ident identified and
00:27:12 --> 00:27:16 analyzed uh collect in a group that is
00:27:16 --> 00:27:19 has got the wonderful name of group four
00:27:19 --> 00:27:21 uh which presumably means there's
00:27:21 --> 00:27:23 another three as well.
00:27:23 --> 00:27:27 >> Yeah. U and it's uh the again what makes
00:27:27 --> 00:27:30 them stand out in this group is the
00:27:30 --> 00:27:33 oxygen isotope signature that I just
00:27:33 --> 00:27:35 mentioned before. It's depleted in uh an
00:27:35 --> 00:27:40 isotope called oxygen 16. But here's
00:27:40 --> 00:27:42 where the story gets very interesting
00:27:42 --> 00:27:44 because
00:27:44 --> 00:27:49 um no known meteorites have that same
00:27:49 --> 00:27:51 oxygen isotope signature.
00:27:51 --> 00:27:55 >> And you'd expect uh if these things were
00:27:55 --> 00:27:58 common that there would be meteorites uh
00:27:58 --> 00:28:01 that match them in their composition. Uh
00:28:01 --> 00:28:03 and often with meteorites we can get an
00:28:04 --> 00:28:06 idea where they've come from. uh most of
00:28:06 --> 00:28:08 them come from the asteroid belt from
00:28:08 --> 00:28:11 collisions between asteroids. Uh so uh
00:28:11 --> 00:28:14 that um you know that is a bit
00:28:14 --> 00:28:16 mysterious that we've got these
00:28:16 --> 00:28:20 subatomic sorry these small ferals of
00:28:20 --> 00:28:22 material that have come down through the
00:28:22 --> 00:28:25 atmosphere uh and got that globular
00:28:25 --> 00:28:28 shape. Um it it's mysterious that we
00:28:28 --> 00:28:31 don't know we don't see any meteorites
00:28:31 --> 00:28:35 that match their composition. weird.
00:28:35 --> 00:28:38 >> It is weird. Yes. Uh and so what they're
00:28:38 --> 00:28:42 suggesting is that um it's basically
00:28:42 --> 00:28:44 something that that comes from an
00:28:44 --> 00:28:47 asteroid whose uh whose characteristics
00:28:47 --> 00:28:51 are unusual uh that we have not uh yet
00:28:51 --> 00:28:53 um identified it.
00:28:53 --> 00:28:58 >> Wow. Okay. So we're still looking.
00:28:58 --> 00:29:00 >> We're still looking. There's a a sort of
00:29:00 --> 00:29:05 sub mystery as well because um the a
00:29:05 --> 00:29:07 detailed analysis of this. You can break
00:29:07 --> 00:29:09 that group four stuff down into other
00:29:09 --> 00:29:13 smaller groups and uh some of them
00:29:13 --> 00:29:15 basically show signs of having had two
00:29:16 --> 00:29:19 different uh minerals in them before
00:29:20 --> 00:29:22 they entered the earth's atmosphere. Um
00:29:22 --> 00:29:25 and um one would be typical of
00:29:25 --> 00:29:28 well-known uh well-known types of
00:29:28 --> 00:29:31 asteroids and the other as I said
00:29:31 --> 00:29:33 doesn't correspond to any kind of known
00:29:33 --> 00:29:38 um group of uh of um cosmic ferals or
00:29:38 --> 00:29:42 meteorites. Uh and it's really quite
00:29:42 --> 00:29:44 remarkable that this you know we're
00:29:44 --> 00:29:46 being bombarded by dust particles that
00:29:46 --> 00:29:49 come from somewhere which we haven't
00:29:49 --> 00:29:50 identified.
00:29:50 --> 00:29:53 >> Yeah. Wow. Um, could that mean they're
00:29:53 --> 00:29:55 from beyond our system or it's just a
00:29:55 --> 00:29:58 part of the system that we
00:29:58 --> 00:30:00 >> I think it's I don't know.
00:30:00 --> 00:30:02 >> Yeah, I think it's the other way around.
00:30:02 --> 00:30:05 Um because the um the team who have done
00:30:05 --> 00:30:07 the research on this a very very
00:30:07 --> 00:30:08 thorough piece of research
00:30:08 --> 00:30:11 >> they've basically
00:30:11 --> 00:30:14 um as you would you've used simulations
00:30:14 --> 00:30:17 computer simulations to to essentially
00:30:17 --> 00:30:20 work out what conditions these things
00:30:20 --> 00:30:23 formed in when they um melted coming
00:30:23 --> 00:30:26 through the earth's atmosphere. And it
00:30:26 --> 00:30:28 suggested that the best fit they get to
00:30:28 --> 00:30:30 what they see, the the sort of textures
00:30:30 --> 00:30:33 that are in the material fit with
00:30:34 --> 00:30:37 relatively low velocities, 14 to 17
00:30:37 --> 00:30:39 kilometers/s
00:30:39 --> 00:30:42 uh which is pretty speedy when you think
00:30:42 --> 00:30:45 of it on Earth, but um uh in space
00:30:45 --> 00:30:47 that's that's a fairly modest uh space
00:30:47 --> 00:30:49 speed for a meteorite. They typically
00:30:49 --> 00:30:52 will be more like 30 kilometers/s.
00:30:52 --> 00:30:56 And so that low value uh suggests that
00:30:56 --> 00:31:01 possibly those particles originated in
00:31:01 --> 00:31:06 near-Earth asteroids um ones that are uh
00:31:06 --> 00:31:07 following a similar path through space
00:31:08 --> 00:31:11 to the Earth. Uh, and that might mean
00:31:11 --> 00:31:15 that we've got some sort of uh in in the
00:31:15 --> 00:31:17 Earth's environment, some sort of
00:31:17 --> 00:31:21 unusual asteroid that is not matched by
00:31:21 --> 00:31:22 all the ones that we know already.
00:31:22 --> 00:31:25 >> Wow, that'd be something. Uh, that's
00:31:25 --> 00:31:26 probably going to be hard to track down,
00:31:26 --> 00:31:27 though.
00:31:27 --> 00:31:29 >> Yes. Yes, that's probably right. And
00:31:29 --> 00:31:30 especially since it might not exist
00:31:30 --> 00:31:32 anymore. It may have collided and formed
00:31:32 --> 00:31:33 little bits that have
00:31:33 --> 00:31:35 >> basically rained down on the Earth.
00:31:35 --> 00:31:35 >> Yeah.
00:31:36 --> 00:31:38 >> Now, it wasn't fear, Rusty. just throw.
00:31:38 --> 00:31:40 >> No, it wasn't here. That's right. Yeah,
00:31:40 --> 00:31:42 thanks Rusty. It's not here.
00:31:42 --> 00:31:44 >> Um, for the record, Brownley particles
00:31:44 --> 00:31:47 and cosmic fererals are closely related,
00:31:47 --> 00:31:49 but they are not exactly the same thing.
00:31:49 --> 00:31:50 >> Okay,
00:31:50 --> 00:31:52 >> they represent two different stages or
00:31:52 --> 00:31:55 types of micrometeorites.
00:31:55 --> 00:31:57 >> There you go. Thank you for checking
00:31:57 --> 00:31:58 that. Yes,
00:31:58 --> 00:31:59 >> that's all right. Um, yeah, they're very
00:32:00 --> 00:32:01 close, but they're not not the same.
00:32:01 --> 00:32:02 >> So, I was on the right track.
00:32:02 --> 00:32:05 >> You were. Yes.
00:32:05 --> 00:32:07 And you can read all about that at uh
00:32:07 --> 00:32:11 the Daily Galaxy website. Um and the
00:32:11 --> 00:32:14 article was published where Fred of Lost
00:32:14 --> 00:32:16 Science Advances.
00:32:16 --> 00:32:17 >> Science advances. That's right.
00:32:17 --> 00:32:18 >> Yes.
00:32:18 --> 00:32:19 >> Want to read the whole thing before bed
00:32:19 --> 00:32:22 so you sleep well.
00:32:22 --> 00:32:23 >> Yep.
00:32:23 --> 00:32:24 >> Yeah. This is Space Nuts with Andrew
00:32:24 --> 00:32:28 Dunley and Professor Fred Watson.
00:32:28 --> 00:32:30 We choose to go to the moon in this
00:32:30 --> 00:32:33 decade and do the other things not
00:32:33 --> 00:32:35 because they are easy but because they
00:32:35 --> 00:32:36 are hard.
00:32:36 --> 00:32:38 >> These nuts.
00:32:38 --> 00:32:41 >> Our final story today takes us to the
00:32:41 --> 00:32:43 edge of our galaxy. Well, it takes us
00:32:43 --> 00:32:45 from the center of our galaxy right out
00:32:45 --> 00:32:47 to the edge of our galaxy because we're
00:32:47 --> 00:32:48 talking about the whole thing locktock
00:32:48 --> 00:32:52 and barrel. And it appears, Fred, with
00:32:52 --> 00:32:55 some very clever scientific brains in
00:32:55 --> 00:32:57 action, that our galaxy stretches out
00:32:57 --> 00:33:00 further than we thought.
00:33:00 --> 00:33:02 Uh, it does. It looks as though the
00:33:02 --> 00:33:04 spiral arms are longer than we thought
00:33:04 --> 00:33:05 they were.
00:33:05 --> 00:33:08 >> Uh, and I think this is a very nice
00:33:08 --> 00:33:11 piece of work. Uh, as as I hinted
00:33:11 --> 00:33:14 before, uh, partly because it uses a a
00:33:14 --> 00:33:16 technique that I think is really
00:33:16 --> 00:33:17 extraordinary. It's a very powerful
00:33:18 --> 00:33:19 technique uh using what we call light
00:33:19 --> 00:33:24 echoes. So um so the story basically to
00:33:24 --> 00:33:27 set this in context, it's very hard for
00:33:27 --> 00:33:29 us to produce a map of what our own
00:33:29 --> 00:33:31 galaxy looks like. And that's because
00:33:31 --> 00:33:34 we're embedded in one of the spiral
00:33:34 --> 00:33:37 arms. Uh the stars that we see when we
00:33:37 --> 00:33:39 look at the Milky Way, they're stars
00:33:39 --> 00:33:42 that fellow travelers in the spiral arms
00:33:42 --> 00:33:44 with our sun and solar system, but they
00:33:44 --> 00:33:46 only go out to a thousand lighty years
00:33:46 --> 00:33:48 or so because the spiral arms are so
00:33:48 --> 00:33:51 dusty that you can't really penetrate
00:33:51 --> 00:33:53 much beyond that. Um, and if you were
00:33:53 --> 00:33:57 relying only on visible light,
00:33:57 --> 00:34:00 uh, it would be like trying to draw a
00:34:00 --> 00:34:04 map of the whole of do from standing
00:34:04 --> 00:34:08 outside do jail there on, um, forgotten
00:34:08 --> 00:34:10 this mquarry street.
00:34:10 --> 00:34:11 >> Mcquaryy Street. Yeah.
00:34:11 --> 00:34:13 >> Yes. Yes. Oh, for the record, they're
00:34:13 --> 00:34:15 putting a they've t they've taken down
00:34:15 --> 00:34:17 the public building in front of the old
00:34:17 --> 00:34:19 do jail, which is now a tourist tourist,
00:34:19 --> 00:34:21 and they're turning it into a public
00:34:21 --> 00:34:23 common.
00:34:23 --> 00:34:24 >> I like that idea. That's that's going to
00:34:24 --> 00:34:26 look very nice when it's done.
00:34:26 --> 00:34:28 >> So So that would improve your view of
00:34:28 --> 00:34:30 the city of do, but it still might not
00:34:30 --> 00:34:33 let you make a map of DO from
00:34:33 --> 00:34:35 >> from just there. And that's how we are
00:34:35 --> 00:34:37 in our galaxy. If you're relying on
00:34:37 --> 00:34:39 visible light observations,
00:34:40 --> 00:34:42 uh you're all you're seeing when you
00:34:42 --> 00:34:45 look is the is the neighborhood of our
00:34:45 --> 00:34:47 spiral arm, a local spiral arm. You
00:34:47 --> 00:34:49 don't get any hint or inclination of the
00:34:49 --> 00:34:52 structure of the galaxy uh beyond that.
00:34:52 --> 00:34:55 And in particular,
00:34:55 --> 00:34:57 you know, if we see a a thousand lighty
00:34:57 --> 00:34:59 years or so, there's another 100
00:34:59 --> 00:35:01 that we're not seeing because that's
00:35:01 --> 00:35:04 about the diameter of our galaxy. So um
00:35:04 --> 00:35:07 the situation improves when you use uh
00:35:07 --> 00:35:09 infrared radiation. You can sort of
00:35:09 --> 00:35:12 penetrate uh through the dust and see
00:35:12 --> 00:35:14 actually the center towards the center
00:35:14 --> 00:35:16 of our galaxy. That's how we know about
00:35:16 --> 00:35:17 the black hole in the center of our
00:35:17 --> 00:35:19 galaxy because we could see stars
00:35:19 --> 00:35:22 orbiting around it. Um but it improves
00:35:22 --> 00:35:25 even more on a broader scale if you can
00:35:25 --> 00:35:27 use radio telescopes because you can
00:35:27 --> 00:35:31 plot uh where the clouds of hydrogen gas
00:35:31 --> 00:35:34 cold hydrogen uh which radiates in radio
00:35:34 --> 00:35:38 waves uh with a wavelength of 21 cm uh
00:35:38 --> 00:35:40 that you can plot out. But if you're
00:35:40 --> 00:35:42 going to try and draw a map, you do need
00:35:42 --> 00:35:43 to do some modeling with that. You've
00:35:43 --> 00:35:45 got to assume things about the rotation
00:35:45 --> 00:35:47 of the galaxy. So it doesn't just give
00:35:47 --> 00:35:50 you a direct map. And that could be
00:35:50 --> 00:35:52 wrong. We could have that little bit of
00:35:52 --> 00:35:55 it wrong. Uh you know the uh the stuff
00:35:55 --> 00:35:57 that comes from the radio observations.
00:35:58 --> 00:36:02 So what's happened now is it's a team uh
00:36:02 --> 00:36:06 I think they're based in Italy. Uh and
00:36:06 --> 00:36:09 what they've done is used
00:36:09 --> 00:36:14 um a direct method of kind of setting up
00:36:14 --> 00:36:16 a standard ruler. Uh because if you've
00:36:16 --> 00:36:18 got a standard ruler and you can see it
00:36:18 --> 00:36:20 in deep space, then you you know how far
00:36:20 --> 00:36:21 away it is because you know you can
00:36:21 --> 00:36:23 measure how long it appears to be. And
00:36:23 --> 00:36:25 if you know how long it is, which is
00:36:25 --> 00:36:27 what a standard ruler is, then you know
00:36:27 --> 00:36:30 how far away it is. Um and that's what
00:36:30 --> 00:36:32 they're doing. They have and and it goes
00:36:32 --> 00:36:34 back to something we mentioned earlier
00:36:34 --> 00:36:36 in the show, gammaray bursts, these
00:36:36 --> 00:36:39 burst of gamma radiation.
00:36:39 --> 00:36:42 uh those bursts uh don't just directly
00:36:42 --> 00:36:45 come to us, they also bounce off or are
00:36:45 --> 00:36:48 reflected by clouds of dust in our
00:36:48 --> 00:36:54 spiral arms. And uh so by timing how
00:36:54 --> 00:36:58 long uh it takes for these echoes as
00:36:58 --> 00:37:00 they're called light echoes even though
00:37:00 --> 00:37:03 it's gamma radiation uh to what the
00:37:03 --> 00:37:07 delay is between a light echo and the uh
00:37:07 --> 00:37:09 source itself which is the gammaray
00:37:09 --> 00:37:11 burst I should say they probably come
00:37:11 --> 00:37:14 from collapsing mass massive stars or
00:37:14 --> 00:37:17 merger of neutron stars uh very
00:37:17 --> 00:37:19 energetic events because they they're
00:37:19 --> 00:37:21 bright in gamma radiation. Uh but if you
00:37:21 --> 00:37:23 look at a light echo from a gammaray
00:37:23 --> 00:37:26 burst, it gives you a scale to this. You
00:37:26 --> 00:37:31 you know um how far uh basically it
00:37:31 --> 00:37:33 gives you a standard ruler um because
00:37:33 --> 00:37:35 you can time it accurately. You know
00:37:35 --> 00:37:37 that 300 kilometers/s is the speed
00:37:38 --> 00:37:40 of gamma rays through space. And you
00:37:40 --> 00:37:42 know if you know how far away it's gone
00:37:42 --> 00:37:43 in that time, then that gives you a
00:37:43 --> 00:37:45 distance measure. So you've got a
00:37:45 --> 00:37:48 standard ruler. Uh it's a very very nice
00:37:48 --> 00:37:51 way of doing this. And um using that uh
00:37:51 --> 00:37:55 these uh scientists um as I said at
00:37:55 --> 00:37:57 least the lead the lead author is
00:37:57 --> 00:38:00 certainly in Italy at Enough in Milano.
00:38:00 --> 00:38:03 Uh they uh they've done this work
00:38:03 --> 00:38:05 looking at these gammaray bursts with
00:38:05 --> 00:38:08 their light echoes and that allows them
00:38:08 --> 00:38:11 to calculate basically the size of our
00:38:11 --> 00:38:13 spiral arms without relying on any kind
00:38:13 --> 00:38:15 of modeling. M
00:38:15 --> 00:38:19 >> uh and so they think that the new
00:38:19 --> 00:38:22 observations indicate that our spiral
00:38:22 --> 00:38:25 arms are something like 10% longer than
00:38:25 --> 00:38:26 we thought they were.
00:38:26 --> 00:38:27 >> Wow. That's a lot.
00:38:27 --> 00:38:29 >> And yes, that's significant, isn't it?
00:38:29 --> 00:38:32 It's it's really um you know, this is,
00:38:32 --> 00:38:34 as I said, this is very nice uh nice
00:38:34 --> 00:38:35 astronomy.
00:38:35 --> 00:38:39 >> It is indeed. Yeah. Um of course, as you
00:38:39 --> 00:38:41 say, we we can't really look at our
00:38:41 --> 00:38:43 galaxy and we don't know exactly what it
00:38:43 --> 00:38:45 looks like. Um there's a lot of science
00:38:45 --> 00:38:48 that they've put together to try and
00:38:48 --> 00:38:50 create the image of it. And even in this
00:38:50 --> 00:38:52 particular story, uh which is in the
00:38:52 --> 00:38:54 universetoday.com, they've got an
00:38:54 --> 00:38:57 artist's impression of what this new
00:38:57 --> 00:38:58 look is like.
00:38:58 --> 00:38:59 >> Yes, that's all you can do.
00:38:59 --> 00:39:03 >> Reminds me of an upside down snail.
00:39:03 --> 00:39:05 >> It does. Yes, that's right. A bit.
00:39:05 --> 00:39:08 >> I see what you mean. Yes. Yes. It's very
00:39:08 --> 00:39:09 much very helpful.
00:39:09 --> 00:39:10 >> Or a squid.
00:39:10 --> 00:39:12 >> Could be a squid.
00:39:12 --> 00:39:15 >> Could be a squid. Yeah. Uh but in real
00:39:15 --> 00:39:18 terms, we just have to it's an educ a
00:39:18 --> 00:39:20 very very well educated guess, I
00:39:20 --> 00:39:21 suppose.
00:39:21 --> 00:39:24 >> Um it's Yes, it is. It's it's a
00:39:24 --> 00:39:27 measurement. So it's it's a it's it's an
00:39:27 --> 00:39:28 you're right. It's an artist's
00:39:28 --> 00:39:29 impression. That's really the only way
00:39:29 --> 00:39:31 we can depict the Milky Way. Some of the
00:39:32 --> 00:39:33 depictions are very very good and they
00:39:33 --> 00:39:35 rely on the very best radio and infrared
00:39:36 --> 00:39:38 observations that have been made. But
00:39:38 --> 00:39:40 this is going to modify it a little bit
00:39:40 --> 00:39:42 by our new knowledge of the spiral arms.
00:39:42 --> 00:39:46 And I should say um the um it's the
00:39:46 --> 00:39:50 Chandra satellite uh which is an X-ray
00:39:50 --> 00:39:54 observatory um by operated by NASA uh
00:39:54 --> 00:39:56 that has been used to make the
00:39:56 --> 00:39:59 measurements. And I do like the headline
00:39:59 --> 00:40:01 on a little uh NASA video that there is
00:40:01 --> 00:40:04 here which is NASA's Chandra examines
00:40:04 --> 00:40:06 Milky Way at arms length.
00:40:06 --> 00:40:08 >> Yeah.
00:40:08 --> 00:40:11 Well done. Very well done. Clever clever
00:40:11 --> 00:40:12 those words.
00:40:12 --> 00:40:13 >> Yeah, they are there some good people
00:40:13 --> 00:40:14 there.
00:40:14 --> 00:40:16 >> So, the articles in universe today, but
00:40:16 --> 00:40:19 you can read it in a deeper form through
00:40:19 --> 00:40:23 the NASA website or the uh astronomy and
00:40:23 --> 00:40:25 astrophysics journal I think is
00:40:25 --> 00:40:27 published uh the full paper which is um
00:40:27 --> 00:40:30 yeah
00:40:30 --> 00:40:30 journal
00:40:30 --> 00:40:33 >> lots of numbers in it. Yeah, lots and
00:40:33 --> 00:40:36 lots of numbers. numbers that are too
00:40:36 --> 00:40:39 big for my brain.
00:40:39 --> 00:40:41 >> All right. Uh that's where we end the
00:40:41 --> 00:40:43 show, Fred. Thank you very much.
00:40:43 --> 00:40:46 >> Oh, a pleasure. Uh some, as you said at
00:40:46 --> 00:40:48 the beginning, some nice stories there
00:40:48 --> 00:40:49 to share them with.
00:40:49 --> 00:40:50 >> Indeed.
00:40:50 --> 00:40:52 >> Uh we'll catch you real soon. Thank you,
00:40:52 --> 00:40:53 Fred.
00:40:53 --> 00:40:54 >> Always. Thanks, Andrew.
00:40:54 --> 00:40:55 >> Professor Fred Watson, astronomer at
00:40:56 --> 00:40:57 large. And uh as I say, between
00:40:57 --> 00:40:59 episodes, visit our website,
00:40:59 --> 00:41:00 spacenutspodcast.com
00:41:00 --> 00:41:02 or spacenuts.io
00:41:02 --> 00:41:05 if you're a lazy typist. And you can
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00:41:19 --> 00:41:21 of Space Nuts, your favorite podcasting
00:41:22 --> 00:41:23 platform. And thanks to Hugh in the
00:41:23 --> 00:41:26 studio because he didn't turn up today.
00:41:26 --> 00:41:28 And from me, Andrew Duckling. Whoops.
00:41:28 --> 00:41:29 Uh, thanks for your company. We'll catch
00:41:29 --> 00:41:31 you on the next episode of Space Nuts.
00:41:31 --> 00:41:32 Bye-bye.
00:41:32 --> 00:41:34 >> Space Nuts. You'll be listening to the
00:41:34 --> 00:41:37 Space Nuts podcast
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